Insight into the thermal stability, structural change and rheological property of wheat gluten treated by superheated steam during hydration

In this paper, the effect of superheated steam treatment (SST) on the thermal， structural and rheological properties of wheat gluten were investigated. The results of low-field nuclear magnetic resonance (LF NMR) illustrated that SST weakened the interaction between water and gluten during hydration. The denaturation of gluten proteins under high temperature broadened exotherm and increased the enthalpy (ΔH) values of differential scanning calorimeter (DSC), increasing from 2.35 J/g (native gluten) to 2.76 J/g (native gluten treated at 150 °C for 4 min). In addition, the increase of degradation temperature indicated that SST enhanced the thermal stability of hydrated gluten. Confocal laser scanning microscopy (CLSM) was employed to observe the micro-structure of hydrated gluten network, indicating that hydrated gluten could not form network structure after SST. This weakened viscoelastic characteristics were linked to the weakened hydrated gluten network structure. The results of the current work help to understand the improvement of wheat flour quality following SST.